ITaskGroup

The ITaskGroup interface is implemented in EXPLORER.EXE
by a class that is named internally as CTaskGroup. The
interface is thought to be used only within EXPLORER. Yet it is certainly no mere
implementation detail with no effects outside EXPLORER. The class models a group
of taskbar buttons whose corresponding windows are judged by Microsoft to be so
similar that they must be grouped together on the taskbar and thereafter kept together
as a unit whether as separate buttons or combined into one. Any attempt at putting
users in control of this grouping, whether to disable it altogether or to undo a
particular group or even just to reorder the buttons within a group, will require
a good understanding of this class and its interface.

Please note that the interface is not only internal to EXPLORER.EXE but is highly
variable from one Windows version to another. At least Microsoft has changed the
IID each time the interface has changed substantively, which has not always been
its practice with COM interfaces in the shell. Beware, however, that these notes
have been prepared only from inspection of the original release of each version.

Interface

IID

Versions

ITaskGroup

{D2C5AD6A-C4C5-4DE1-AE35-59A809405534}

6.1 only

{C499358F-5DF6-4E9A-826C-05B6CAD5BEFD}

6.2 to 6.3

{3AF85589-678F-4FB5-8925-5A134EBF572C}

10.0 only

No evidence is known that Microsoft defines the conventional symbol
IID_ITaskGroup for this interface’s IID. Microsoft’s
names and types for the ITaskGroup methods are known
from the public symbol files for EXPLORER.EXE. The presentation here follows the
ordering of the virtual function table after the IUnknown
methods.

Among the types that can be passed as arguments or be produced at addresses that
are passed as arguments, IEnumTaskItems,
ITaskItem and ITaskItemFilter
are undocumented COM interfaces and WINDOWMATCHCONFIDENCE
is an undocumented enumeration.

This page was created on 10th February 2018 but was not published
until 13th June 2018.